Outline

Objective: Comparison of surgical resection results of brainstem cavernomas with and without neuronavigation including fiber tracking . Do modern methods of monitoring lead to a reduction in postoperative disability (hemiparesis, cranial nerve dysfunction, ataxia and balance disturbances)?

Methods: Between 1998 and 2010, 19 patients with brainstem cavernomas were treated surgically in our department. The locations were as follows: midbrain 6, midbrain and the IV ventricle 1, pons 7, middle and inferior cerebellum peduncles 3, medulla oblongata 2. The indication for surgery was intraparenchymal bleeding – often recurrent or with associated increasing neurological deficits. By the year 2005, we had operated on 8 patients; after 2005 we operated 11 patients with the neuronavigation/tractography of white matter tracts. Intraoperatively we performed: somatosensory evoked potentials and motor nuclei stimulation of the cranial nerves VII, IX, X and XII. Starting in 2009, motor evoked potentials were also used. Infratentorial, supracerebellar access was used in case of midbrain location, access through the bottom of the IV ventricle was used in case of pons and medulla oblongata location as well as the subtonsillar location, transcerebello-medullary fissure access was used for lesions of the middle peduncle, and the subtonsillar approach was used to access the inferior cerebellum peduncule cavernomas.

Results: In the period 1998–2005, total resection was achieved in 5 cases (62.5%) and partial resection was achieved in 3 cases (37.5%). After the introduction of neuronavigation/tractography, total resection could be achieved in all 11 cases (100%). Persistent hemiparesis occurred more often in the period before we implemented neuronavigation/tractography; no patients presented with additional limb paresis after this technology was introduced. However, this technology did not affect the postoperative degree of damage to the cranial nerves (new deficits were observed). There was no long-term increase in ataxia and gait disturbances at follow-up since the initiation of neuronavigation of cerebellar white matter tracts.

Conclusions: The use of neuronavigation/tractography increased the totality of cavernoma resection. Postoperative persistent hemiparesis occurs less often since the initiation of neuronavigation/tractography. Neuronavigation has no impact on postoperative cranial nerve dysfunction. Tractography of spino-cerebellaris and cerebello-ponto-thalamo-corticalis white matter tracts within the neuronavigation system can diminish postoperative ataxia and gait disturbances.